In treating organs such as the heart, access by surgeons have typically involved an invasive procedure such as a sternotomy, thoracotomy, as well as subxiphoid incisions along with retraction of the sternum to expose the anterior pericardium. Such procedures are typically employed to dislodge the heart to provide access to various regions of the heart tissue. Moreover, procedures such as thoracotomies may additionally require the deflation of one or both lungs to provide the necessary access. However, because of their invasive nature, such procedures are not desirable.
Minimally invasive surgeries may employ small, access incisions or utilize ports, yet because such procedures are typically employed while under the direct vision of the surgeon, fairly large incisions are still utilized to provide the surgeon a direct view of the surgical field. Other minimally invasive procedures have utilized endoscopic devices and instruments which are introduced within the thoracic cavity via one or more ports positioned within the intercostal spaces. However, such methods fail to allow access to all regions of the heart by the surgeon.
Moreover, other conventional procedures, whether open heart surgery or minimally invasive surgery, typically require a relative large incision in the pericardium to expose the heart. As the heart typically underlies the pericardium, incising the pericardial sac without inadvertently damaging the heart tissue is typically handled by creating a second incision into the thoracic cavity. A separate instrument, such as graspers or forceps, is introduced into the chest to pull the pericardium away from the heart to allow for an incision to be made into the pericardial sac. However, this requires multiple incisions to be made into the patient and the advancement of multiple instruments in separate passageways.
Such incisions through the pericardium are desirably left as small as possible to reduce fibrous adhesions to the heart. Thus, dilating instruments are desirably as small as possible to minimize any trauma to the tissue. However, typical dilators such as balloon dissectors exert shear forces on the surrounding tissue as they are advanced in the body.
Thus, it is desirable to provide apparatus and methods which provide for relatively safe and minimally invasive access to all regions of the heart in an atraumatic manner while under direct visualization without having to provide additional incisions into the patient body.